Shearing bar for planing machines



Dec. 9, 1947. 2,432,190

SHEARING BAR FOR PLANING MACHINES Filed Dec. 18, 1944 DEL . Inuenfor B3 NEvereflDicK mfl/axaw Arrbrneg Patented Dec. 9, 1947 SHEARING BAR FOR PLANIN G MACHINES M. Everett Dick, Holland, Mich., assignor to Buss Machine Works, Holland, Mich., a. corporation of Michigan Application December 18, 1944, Serial No. 568,682

2 Claims. 1

This invention relates to a shearing bar .for wood planing or surfacing machines and the means to prevent knots or pieces of wood from becoming jammed between the cutter head and the pressure bar where they would damage either said cutter head or pressure bar or both.

A great deal of trouble has been experienced in planing machines because loose knots or small pieces of wood would find their way to the rapidly rotating cutter head and would be carried around by the knives and become jammed or wedged against the pressure bar either bending or breaking it, damaging the knives and sometimes damaging the bearings of the cutter head. This would put the machine out of operation for a considerable time and entail a great deal of expense in repairs.

An understanding of the invention may be had from the following description and the accompanying drawings, in which Fig. 1 is a fragmentary vertical section through the upper part of a planer at the cutter head portion thereof illustrating the shearing bar of my invention in transverse section.

Fig. 2 is a fragmentary end elevation showing the shearing bar in longitudinal elevation and its place of mounting at the upper side of the back pressure bar.

Like reference characters refer to like the figures of the drawing.

The environment in which the invention is used is that of a wood planer having a table I above which a cylinder 2 is mounted for rotation upon a horizontal shaft, the cylinder carrying cutting knives 3, the outer edges of which are sharpened and which outer edges move in what is termed a cutting circle, coming in rapid succession to the surface of a board 4 which is fed between the table and the cutter head by a plurality of feeding rollers such as indicated at 5. Over the upper side of the elongated cutter head or cylinder the outlet hood 6 for a vacuum exhaust system is mounted, the vacuum system being operated by a suction fan as usual in constructions of this kind for withdrawing the loose material which is cut from the surface of the board by the cutting knives.

The back pressure bar of planer machines is mounted upon and below a horizontal mounting bar 1 which at its ends is carried upon the side frame members of the planing machine. At each end of the bar 1 such elements as indicated at B for adjusting said bar I in a vertical direction are positioned below the ends of the bar. A rod 9 threaded at its upper and lower ends passes through each end of the bar 1 screwing into a suitparts in 2 able interiorly threaded socket in the side frame of the machine. Over each end of the bar 1 a heavy coiled compression spring I'D is positioned above which are two spaced apart nuts II threaded on the upper end portion of the rod 9 and between which is a disk I'2 as shown.

The back pressure bar l3 which pressed against the upper side of the board 4 which is being operated upon extends lengthwise of the cutter head and is located underneath the mounting bar 1. It is secured in place by bolts or cap screws [4 which pass through the bar I into the back pressure bar I3. The shearing bar which I use in my invention consists of hardened steel bar l5 extending the full length of the cutter head and clamped between the mounting bar 1 and the back pressure bar Hi. It extends toward the cutter head and has its inner edge beveled upwardly and inwardly toward the cutter head, lying close to the cutting circle of the head so that the knives, when rotating, pass at their sharpened edges closely adjacent to the inner edge of the shearing bar which is also sharpened to a cutting edge.

The chip breaker i6 is located forwardly of the cutter head and extends transversely of the machine the full length of the cutter head. Its lower edge rides upon the upper surface of the work and it is substantially arcuate in shape and, so far as the invention is concerned, it serves to guide shavings or chips and loose knots and small pieces of wood upwardly with the rotation of the cutter head toward the exhaust hood 6. The light particles such as chips or shavings are drawn upwardly by suction through the hood and exhaust system but the suction is not sufficiently strong to carry away the heavier objects such as knots and small pieces of wood and they drop downward where they attempt to follow the rotation of the knives and are brought against the shearing bar [5.

In this position the combined action of the sharp edges of the knives and shearing bar cut or chew these pieces into fine particles. The sharpened edge of the shearing bar is set so that the distance between it and the cutter head is no greater than the shortest distance between the cutter head and the pressure bar and therefore no particles can pass the shearing bar which will not also pass between the cutter head and the pressure bar and any pieces of larger dimensions will remain above the shearing bar until they have been cut into small particles by the combined action of the knives and the shearing bar.

Therefore no pieces sufficiently large to wedge between the cutting head and the pressure bar are permitted to reach that location and damage to the machine for that reason is completely eliminated. The device has been thoroughly practiced in commercial use and has been found to operate perfectly on all types of wood and has completely eliminated damage to the machine.

I claim:

1. In a planing, machine, a horizontally mounted rotatable cutter head having knives ex tending therefrom, a pressure bar extending adjacent the cutter head having its lower edge in engagement with the work and extending up wardly alongside the cutter head, a suction hood located over said cutter headand connected with a, source of suction, guide means at the work entrance side of the cutter head for leading chips out from the work upwardly to said suction hood and a shearing bar rigidly mounted near the lower end of said suction hood within the suction area and above said pressure bar and extending to- 20 the cutter head spaced therefrom a distance not greater than the closest distance between cutter head and pressure bar, said shearing bar extending substantially the entire length of the cutter head and being of sufficient strength to stop or break large chunks of material thrown against it by said cutter head.

2; The elements of claim I in. which said shearitr'g' bar has a sharpened edge coacting with the knives of the cutter head to cut up objects lodged upon said shearing bar.

M. EVERETT DICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS I Number Name Date 1,079,032 Solem Nov. 18, 1913 1,240,769 Osteman Sept. 18, 1917 

